need help for Compliation error

Hi everyone,
Anyone know how to solve this error?
Derivative input 1 of 'untitled/Active and Reactive Power control/Integrator2' at time 0 is Inf or NaN. Stopping simulation. There may be a singularity in the solution. If not, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances).

"Jade " <zhengqirong@hotmail.com> wrote in message <ichvts$9ln$1@fred.mathworks.com>...
> Hi everyone,
> Anyone know how to solve this error?
> Derivative input 1 of 'untitled/Active and Reactive Power control/Integrator2' at time 0 is Inf or NaN. Stopping simulation. There may be a singularity in the solution. If not, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances).
>
> Thanks
>
> JAde